I like the poem. I'll split my review into two parts: constructive criticism and positive criticism.

CC: The first line is good, however, I think you should cut out the 'that' in the second line and change 'when' to 'because'. I think "Now I'm blind because it's here" would read better; the word 'that' is unnecessary, and 'when' is not as clear. Again in the third line, take out 'that', as it's not doing anything. :P "Never escape my twisted maze of a mind" is good, but perhaps 'escaped' would work better. Take out the 'too' in the third last line; again, no purpose.
That really is nitpicking, but the poem was good and I have little else to comment on. I think making it clearer would make it more powerful, too.

PC: It is only nine lines, yet it is possibly the best poem about insanity I've read yet. I love the beginning and the ending, and I adore the line in parenthesis as well. I like how it's really long compared to the others; it seems to divide the poem, but the length draws attention to that line. Blood red in parenthesis as well is an interesting effect that works well in context. Personally, I think the poem is about a person going insane, but without knowing what's happening. "They" is probably the society driving them insane, and the sea represents freedom, in my opinion.